Give the molecular formula for indigo.
Name three functional groups present in indigo.
What type of reaction does the conversion of indigo into leuco-indigo involve?
Suggest a laboratory reagent to use in this reaction.
Suggest two chemical tests that could distinguish indigo from leuco-indigo. Present your answers in the table below.
When indigo is heated with hydrogen and a nickel catalyst, compound $A$, $\text{C}_{16}\text{H}_{28}\text{N}_2\text{O}_2$, is produced. Suggest a structure for $A$.
Calculate the volume of hydrogen, at room temperature and pressure, that would be absorbed if $2.50\ \text{g}$ of indigo reacted in this way. volume $= \ldots\ldots\ldots\ldots\ldots\ldots\ldots\ \text{dm}^3$
Suggest the structure of the product formed when indigo reacts with excess $\text{Br}_2\text{(aq)}$.